use object for `rotation` in towers example
use object for `rotation` in towers example

jaxmolina/ar,MatthewShotton/aframe,wizgrav/aframe,wizgrav/aframe,dmarcos/aframe,msimpson/aframe,mkungla/aframe,ngokevin/aframe,jaxmolina/ar,RSpace/aframe,chenzlabs/aframe,googlecreativelab/aframe,chenzlabs/aframe,ngokevin/aframe,aframevr/aframe,msimpson/aframe,darkwing/aframe,darkwing/aframe,RSpace/aframe,aframevr/aframe-core,mkungla/aframe,fernandojsg/aframe,aframevr/aframe,dmarcos/aframe,jzitelli/aframe,googlecreativelab/aframe,weddingdj/aframe,jzitelli/aframe,aframevr/aframe-core,weddingdj/aframe,fernandojsg/aframe,MatthewShotton/aframe